msem-instigator

Molting Abomination can't be blocked by creatures with power 2 or less.
Whenever Molting Abomination deals combat damage to a player or planeswalker, create a tapped 3/2 colorless Horror creature token. Put a stun counter on that token. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Enchant creature
Enchanted creature gets -1/-3.

Flash
When Outland Alchemist enters, return another permanent you control to its owner's hand.

As Game Trail enters, you may reveal a Mountain or Forest card from your hand. If you don't, Game Trail enters tapped.
{T}: Add {R} or {G}.

{T}: Add {C}.
{1}, {T}: Add one mana of any color. When that mana is spent to cast an Adventure spell, scry 1.

Poisonous 1 (Whenever this creature deals combat damage to a player, that player gets a poison counter.)
Duskscale Marauder can't be blocked.

Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)
When Sandstrider enters, put a +1/+1 counter on target creature.

{T}, Pay 1 life, Sacrifice Abbey of Masquerades: Create a tapped Plains token, Island token, Swamp token, Mountain token, or Forest token.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

{T}, Sacrifice Worldshaper Adept: Choose two basic land types. Create a tapped colorless land token of the chosen types.

When Ophidian Oracle enters, draw a card, then abound. (To abound, you may cast a spell that costs less than this from your hand without paying its mana cost.)
Recite {2}{G}{G} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

Flying, hexproof
At the beginning of your end step, put an exiled card with an ancestry counter on it on the bottom of its owner's library, then scry 2. If there is exactly one card exiled with an ancestry counter on it, transform Atieh.

Defender, reach
Bulwark — {X}, {T}: Rampart Ballista deals X damage to each opponent. X can't be greater than the number of creatures you control with toughness 4 or greater.

Put a +1/+1 counter on target creature, then you gain 1 life for each +1/+1 counter among creatures you control.

Converge — Glitch enters with an additional loyalty counter on her for each color of mana spent to cast her.
[+1]: Create two 1/1 blue Elemental creature tokens with flying.
[–3]: Draw two cards. When you do, Glitch deals damage to any target equal to the number of cards in your hand.
[–10]: Destroy all lands, enchantments, and artifacts you don't control.

Counter target spell. If that spell is countered this way, put it on the bottom of its owner's library instead of into that player's graveyard.

Counter target noncreature spell unless its controller pays {1}.
If you control a creature with power 4 or greater, counter that spell instead.

When Steamwork Musicians enters, creatures you control get +1/+0 until end of turn.

Stoic Djinn has flying as long as it has a counter on it.

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
When this creature dies, it deals X damage to target player or planeswalker, where X is the number of cards and tokens merged with it.

Whenever Sir Roger Wimbledon deals combat damage to a player, you may put an exiled creature card you own into your hand.

Scry 2, then create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Monument {2}{R} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Exile target instant or sorcery spell you control. Until end of turn, you may cast that card from exile without paying its mana cost. When you do, copy it. You may choose new targets for the copy.

Choose one —
• Draw three cards.
• Return up to two target creatures to their owners' hands.

{3}, {T}: Ancient Artillery deals 1 damage to target creature or planeswalker and 1 damage to that permanent's controller.